Nanopowders of hydroxyapatite (HA), modified by magnesium (MgHA) and by silicon (SiHA) were obtained by liquid-phase microwave synthesis method. X-ray diffraction and IR spectroscopy results showed that Mg2+ and SiO44− ions were present in the synthesized products both as secondary phases and as part of the HA phase. Whitlockite was found in the magnesium-modified HA (MgHA) and larnite was found in the silicon-modified HA (SiHA); ion substitution for both materials resulted in solid solutions. In the synthesized samples of modified HA, the increase of particle size of powders was in the order HA < SiHA < MgHA, which was calculated through data specific surface area and measured pycnometric density of the powders. The Lewis acid sites (Ca2+, Mg2+, Si4+) were present using spectral probes on the surface of the samples of HA, MgHA, and SiHA, and the acidity of these sites decreased in the order SiHA > MgHA > HA. The rates of calcium phosphate layer deposition on the surface of these materials at 37 °C in the model simulated body fluid solution showed similar dependence.
Relevance of the work is due to the need for new materials that are used in medicine as a substitute for natural bone tissue injuries, fractures, etc. The aim of the work is to obtain composites with improved biocompatible properties based on poly-L-lactide (PLA) and hydroxyapatite (HA) and to perform pilot analysis of interaction PLA, HA, composite PLA-HA with primary human monocytes-derived macrophages in vitro. The pilot experiments using human primary monocytes cultivated on the surface of the samples demonstrated that PLA-HA can stimulate release of anti-inflammatory cytokines that indicates the presence of potential anti-inflammatory properties of the composites
Synthesis of glyoxylic acid was carried out by oxidation of glyoxal aqueous solutions by nitric acid. Glyoxylic acid and oxalic acid (as a by-product) were isolated from technological mixtures in the form of their calcium salts in a strictly defined region of pH. Previously, model calcium salts were synthesized from the commercial acids as reference objects.The results of infrared spectroscopy and complexometric titration of precipitates of calcium salts of glyoxylic and oxalic acids, isolated in various pH regions, allow one to construct reliable research strategies of complex mixtures, such as obtained from the oxidation products of aqueous solutions of glyoxal.
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